Spark plug



L. HIRSCH SPARK PLUG.

vFiled July 25,'` 1924 WITNESSES lzyVENToR,

TTORNEYS..

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Patented Nev. 3, 1925i,

narran LoUIs mason, or Jirnsum. raak,

SPARK rLUG.

Application filed July 26, 15124.

T0 all iii/1.0m t 'may concern.'

Be it known that I, LOUIS Hirsch, a citizen of the United States, and a resident of Mesilla Park, in the county of Dona Ana and State of New Mexico, have invented a new and Improved Spark Plug, of which the following is a full, clear, and exact description.

rlhis invention relates to improvements in spark plugs, an object of the invention being to provide a spark plug with an improved arrangement of electrodes and terminals whereby a pair of sparks is provided at the inner end of the plug, the terminals being in series and grounded through the casing ot the plug.

A further object is to provide a spark plug having an improved construction and arrangement of core and electrodes which result in a plurality7 of sparks spaced an appreciable distance apart, whereby a mairimum or' efficiency is had in the firing of the charge.

lith these and other objects in view, the invention consists in certain novel features of construction and combinations and arrangements of parts which will be more fully hereinafter described and pointed out in the claims.

In the accompanying drawings Figure 1 is a view in longitudinal section illustrating my improved spark plug;

Figure 2 is a view in transverse section on the line 2 2 of Figure 3;

Figure 8 is an inner end view oil' the plug;

Figure 1 is a perspective view of the core removed.

1 represents the casing of my improved plug having an externally screw-threaded inner end 2 for attachment to the engine cylinder. This casing'1 has an internally screw-threaded outer end 3 to receive a nut 4t, the latter functioning to clamp the core 5 securely in the casing 1. The core 5 has an annular enlargement 6 intermediate its ends, and the casing 1 has a shoulder 7 limiting the movement of the core, with a gasket or washer 8 interposed between the enlargement and the shoulder '7, and a gasket 9 interposed between the enlargement 6 and the nut e to render the plug gas tight. The outer portion oi the core 5 is of general cylindrical form while the inner end oit' the core is of general triangular shape in cross Serial No. 728,413.

section, as shown at 10. As the casing l has a general cylindrical bore throughout it will be 'noted that the triangular shape of the inner end of the core provides a space between the same and the casing, and the latter is notched, as shown at 11, at the angles of the core so that ample space is provided for the movement of gases to prevent accumulation of carbon to interfere with the proper operation oit the plug.

The core 5 is provided with three longitudinal openings or bores 12 in which elec` trodes 13, 1t and 15, respectively, are secured. The electrodes 13 and 14 are connected at their outer ends by a link or other conductor 18 and binding posts 16 are pro vided on the outer ends of the electrodes 13 and 15, formed with terminals 19 spaced apart to form a spark gap, and the inner end of terminal 1d is made with a terminal 2O which is spaced from a terminal 21 on the casing 1, torming a second spark gap.

ln operation, the current passes first through electrode 13, then jumps the gap to electrode 15, thence is conveyed by conductor 18 to electrode lll, and jumps the gap to terminal 21, where the current may be grounded. lt is obvious that with a plug ot this type the electrodes may be in circle as above described, or, if desired, the electrodes 13 and 15 may be connected in series or multiple arc with any suitable circuit in accordance with the desires of the trade.

Various slight changes and alterations might be made in the general form of the parts described without departing from my invention, and hence I do not limit myseli1 to the precise details set forth but consider myself at' v.liberty to make such slight changes and alterations as fairly fall within the spirit and scope of the appended claims.

I claim:

1. A spark plug, comprising a casing, a core in the casing, three electrodes in the core, terminals on two of the electrodes forming a spark gap, a terminal on the casing spaced from a terminal on the third electrode forming a second spark gap, and said electrodes connected in series.

2. A spark plug, comprising a casing, a core in the casing, a pair ot electrodes in the core having spaced terminals at their inner ends forming a spark gap, a third electrode inthe core electrically Connected With one of the pair of electrodes, and said third electrode and casing having terminals spaced apart forming a second spark gap.

A spark plug, comprising a casing, a core in the easing, the bore of the easing being cylindrical and the core having an inner end portion of general triangular shape in cross section, three terminals at the inner end of the core adjacent the angles thereof, 10 two of said terminals forming a spark gap, and the third terminal'forming a spark gap with a terminal on the casing, and all of said terminals connected in series.

LOUIS HIRSCH. 

